The present invention relates generally to an electrical connector and, more particularly, to a contact retention assembly for an electrical connector.
Metal contact retention clips are commonly utilized in the electrical connector art for releasably retaining electrical contacts in the insulators of electrical connectors. For example, U.S. Pat. No. 3,158,424 to Bowen discloses the use of a metal contact retention clip having forwardly and inwardly extending retention fingers which engage a shoulder on a contact to retain the contact which is inserted into the insulator from the rear. In order to remove the contact from the insulator, a special tool is inserted into the contact passage from the rear which deflects the retention fingers outwardly beyond the shoulder on the contact thereby releasing the contact.
U.S. Pat. No. 3,246,281 to Cunningham discloses another form of contact retention assembly in which the contact is released from the front rather than the rear of the insulator. In this arrangement, a contact retention clip mounted in the contact passage embodies forwardly extending spring fingers each formed with an internal shoulder which engages a rearwardly facing shoulder on the contact. The forward end of each finger has an internal bevel which extends over the contact in front of the shoulder thereon. The contact may be removed rearwardly from the insulator by inserting a tool into the contact passage from the front of the insulator to engage the beveled surfaces on the fingers, thereby deflecting them radially outwardly from engagement with the shoulder on the contact. Other forms of contact retention clips for either front or rear release of the contacts are well known in the art.
High density contact arrangements in prior art connectors employing contact retention clips as described above are limited because the relatively thin walls of plastic between the contact passages are inadequate to provide the necessary degree of contact-to-contact electrical isolation required to avoid voltage breakdown between the contacts and surface leakage of current from contact to contact. It is, therefore, one object of the present invention to provide a novel contact retention assembly which will permit higher density contact arrangements without impairing electrical isolation between the contacts in the assembly.
The prior art contact retention assemblies utilizing metal retention clips are relatively expensive because of the necessity to assemble a large number of individual clips into the connector insulator. Also, special manufacturing techniques are often required to assure that the clips are retained in the contact passages. Another object of the present invention is to avoid the foregoing assembly problems, as well as the voltage breakdown problems discussed above.
The problem of electrical isolation between the contacts in an electrical connector was addressed in U.S. Pat. No. 2,443,513 to Quackenbush. In this patent, each contact is formed with a pair of axially spaced enlargements providing outwardly facing shoulders. The contact is mounted between front and rear insulators having abutment surfaces thereon which engage the outwardly facing shoulders on the contact to retain the contact in the insulator assembly. In order to raise the permissible voltage between the contacts and to reduce surface leakage of current from contact to contact, an enamel insulating band is provided in the form of a coating over the contact in the region of the two enlargements thereon which is aligned with the interface between the front and rear insulators of the assembly. However, the Quackenbush connector does not employ contact retention clips which would allow individual contacts to be removed from the insulator assembly without removing one of the insulators. Thus, the Quackenbush arrangement is impractical for many applications and does not provide a solution to the problem of providing a high degree of contact-to-contact electrical isolation in an electrical connector employing individual contact retention clips which releasably mount the contacts in the insulator.